How to support this through javax.persistence.StoredProcedureQuery directly is still an open item. I have implemented it on the JPA side just for NamedStoredProcedureQuery via hints. But for JPA StoredProcedureQuery there is a bit of chicken/egg wrt mixed calls to #setHint and #registerStoredProcedureParameter. Meaning to properly support setting this through hints, we'd have to look through hints whenever a parameter is registered and we'd have to look at registered parameter whenever a hint is set. Not a fan of that.